Google has won a resounding victory in its eight-year copyright battle with the Authors Guild over the search giant's controversial decision to scan more than 20 million library and make the available on the internet.

In a ruling (embedded below) issued Thursday morning in New York, US Circuit Judge Denny Chin said the book scanning amounted to fair use because it was "highly transformative" and because it didn't harm the market for the original work.

"Google Books provides significant public benefits," writes Chin, describing it as "an essential research tool" and noting that the scanning service has expanded literary access for the blind and helped preserve the text of old books from physical decay.